“Going after Trump would accomplish little because the businessman’s supporters are deeply committed and unlikely to swing Rubio’s way,” Isenstadt writes. “Inciting a confrontation with Trump onstage would create drama but wouldn’t help the senator gain voters, something he badly needs as he looks for his first primary win.”

Isenstadt said the Rubio campaign believes attacking Cruz is its best bet for attracting more voters. “They think the Texas senator’s voters are less locked in and could swing Rubio’s way should Cruz fade. The only way to dislodge Trump, Rubio’s advisers say, is to turn it into a two-man race — meaning that they first need to get Cruz out of the way.”

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During the previous debates, the rhetoric between Rubio and Trump has not been aggressive. But if Trump decides to challenge Rubio, then the senator’s campaign had better be ready to respond to the challenge.

That’s particularly important in light of Rubio’s disasterous debate performance prior to the New Hampshire primary.

But Rubio’s campaign advisers believe the only way to lessen Trump’s lead is to eliminate the remaining candidates and create a two-man race between Trump and Rubio.

Should this strategy have the intended results, then Rubio would feel free to launch his attack on Trump.